Air compression device

ABSTRACT

The present application discloses an air compression device, including a housing in which an air compressor is stored, the air compressor being configured to generate compressed air; and a filter through which air passes, the air being sucked into the housing. The filter may include a plate member having a first main plate portion provided with air holes through which the air passes. A surface of the first main plate portion is oriented in a first direction, the air holes extending through the plate member in a second direction intersecting with the first direction so as to change a flow direction of the air.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air compression device which isattached to a vehicle.

2. Description of the Related Art

An air compression device is attached to a vehicle (e.g. a train coach).The air compression device generates compressed air to be used in thevehicle (c.f. Japanese Utility Model Registration No. 3150077,hereinafter, simply called as Patent Document 1).

Patent Document 1 discloses an air compression device including filters,air compressors and driving motors. Each of the filters blocks passageof foreign matters (e.g. dust in the air). The air passing through eachof the filters is fed to each of the air compressors. Each of the aircompressors is driven by each of the driving motors for compressing theair.

Patent Document 2 (JP 2010-55973 A) discloses a housing, in which abattery module is stored. The housing is situated beneath a floor of atrain coach. A filter unit is attached to the housing. The filter unitincludes a louver and a filter. The louver prevents intrusion of foreignmatters flying from the front side of the housing. The filter removesdust from the cooling air which is sucked from the outside of thehousing.

The air compression device includes an after-cooler, a dehumidifyingdevice and a housing, in addition to the air compressor and the filter.The after-cooler and the dehumidifying device are stored in the housing.The housing is situated beneath the floor of a vehicle body of the traincoach. The filter is attached to the housing. The air to be compressedby the air compressor is supplied into the housing through the filter.Generally, a filter component made of resin is used as a filter in anair compression device. It is necessary to discard the filter componentmade of resin after use.

When a train runs in a region in which a lot of dust floats, a filtercatches a large amount of dust in a short period of time. Consequently,it is necessary to frequently exchange the filter. The frequent filterexchange results in a large increase in maintenance cost.

An object of the invention is to provide an air compression device whichcontributes to a reduction in maintenance cost for dust removal withoutcausing excessive degradation in dust removal performance.

SUMMARY OF THE INVENTION

An air compression device according to one aspect of the presentinvention includes a housing in which an air compressor is stored, theair compressor being configured to generate compressed air; and a filterthrough which air passes, the air being sucked into the housing. Thefilter includes a plate member having a first main plate portionprovided with air holes through which the air passes. A surface of thefirst main plate portion is oriented in a first direction, the air holesextending through the plate member in a second direction intersectingwith the first direction so as to change a flow direction of the air.

The aforementioned air compression device may contribute to a reductionin maintenance cost for dust removal without excessive degradation indust removal performance.

These and other objects, features and advantages of the aforementionedair compression device will become more apparent upon reading thefollowing detailed description along with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary air compression deviceattached to a vehicle (in a train coach);

FIG. 2 is a plan view schematically showing an attachment position ofthe air compression device in the vehicle;

FIG. 3 is a schematic perspective view of the air compression device;

FIG. 4 is another schematic perspective view of the air compressiondevice;

FIG. 5 is yet another schematic perspective view of the air compressiondevice;

FIG. 6 is still another schematic perspective view of the aircompression device;

FIG. 7 is a schematic view showing a system configuration of the aircompression device depicted in FIG. 3;

FIG. 8 is a schematic perspective view showing one of two air compressorunits in the air compression device depicted in FIG. 6;

FIG. 9 is another schematic perspective view of the air compressor unit;

FIG. 10 is a schematic perspective view showing an internal structure ofthe air compressor unit depicted in FIG. 9;

FIG. 11 is a schematic enlarged front view of a filter;

FIG. 12 is a schematic sectional view taken along the line XII-XII shownin FIG. 11; and

FIG. 13 is a schematic sectional view taken along the line XIII-XIIIshown in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An exemplary air compression device is described below with reference tothe drawings. The principle of the air compression device to beclarified by the following description is widely applicable to a varietyof air compression devices which are attached to train coaches or othervehicles.

[Installation of Air Compression Device]

FIG. 1 is a schematic view of an air compression device 1 attached to avehicle 100. In the present embodiment, the vehicle 100 is a traincoach. Alternatively, the air compression device 1 may be attached toanother vehicle (e.g. an automobile). FIG. 2 is a schematic plan viewshowing an attachment position of the air compression device 1 in thevehicle 100.

As shown in FIGS. 1 and 2, the air compression device 1 includes two aircompressor units 2. The air compression device 1 may include one aircompressor unit Alternatively, the air compression device 1 may includethree or more air compressor units 2. The principle of the embodiment isnot specifically limited by how many air compressor units 2 areincorporated in the air compression device.

The air compression device 1 is attached to a lower portion of a floor100 a of the vehicle 100. Alternatively, the air compression device 1may be attached to another portion of the vehicle 100. The principle ofthe present embodiment is not limited to a specific attachment positionof the air compression device 1.

The air compression device 1 attached to the vehicle 100 uses the aircompressor units 2 to generate compressed air. The vehicle 100 uses thecompressed air to operate various pneumatic devices.

FIG. 2 is a plan view showing a part of the vehicle 100. The aircompression device 1, which is fixed to a lower portion of the floor 100a of the vehicle 100 (i.e.

two air compressor units 2), rails 101 on a railway track, along whichthe vehicle 100 runs, and railroad ties 102 are shown by the two-dottedchain lines in FIG. 2.

The arrow A in FIG. 2 represents the width direction of the vehicle 100.The arrow B in FIG. 2 represents the running direction of the vehicle100. In the following description, a plane of the vehicle 100 extendingalong the direction of the arrow substantially perpendicular to theground is called as “side surface 100 b”. The air compression device 1is situated along a plane extending downward from the side surface 100b. In the present embodiment, the vehicle side surface is exemplified bythe side surface 100 b.

The two air compressor units 2 are fixed to the lower portion of thefloor 100 a of the vehicle 100 so that the air compressor units 2 arealigned in series in the running direction of the vehicle 100.

[Overall Configuration of Air Compression Device]

FIG. 3 is a schematic perspective view of the air compression device 1.FIG. 3 mainly shows the front surface and the bottom surface of the aircompression device 1. FIG. 4 is another schematic perspective view ofthe air compression device 1. FIG. 4 mainly shows the rear surface andthe bottom surface of the air compression device 1. FIG. 5 is yetanother schematic perspective view of the air compression device 1. FIG.5 mainly shows the front surface and the top surface of the aircompression device 1. FIG. 6 is still another schematic perspective viewof the air compression device 1. FIG. 6 mainly shows an internalstructure of the air compression device 1. FIG. 7 is a schematic viewshowing a system configuration of the air compression device 1.

As described above, the air compression device 1 includes the two aircompressor units 2. In addition, the air compression device 1 includes acase unit 11 as shown in FIGS. 3 to 6. The case unit 11 includes twoindividual cases 12. The individual cases 12 are prepared incorrespondence to the air compressor units 2.

When the air compression device includes one air compressor unit 2, anindividual case 12 is used as the case unit. When the air compressiondevice includes three or more air compressor units 2, individual cases12 more than two are used as the case unit. Therefore, the principle ofthe present embodiment is not limited to how many individual cases 12are incorporated in the air compression device.

In the present embodiment, the housing is exemplified by one of the twoindividual cases 12. Each of the two individual cases 12 functions asthe housing for holding each of the two air compressor units 2.

Each of the two individual cases 12 includes frame pieces 12 a (c.f.FIG. 6) and panels 12 b. The frame pieces 12 a and the panels 12 b areassembled into a rectangular box. The panels 12 b are attached to theframe pieces 12 a so as to surround the air compressor unit 2. Each ofthe panels 12 b is formed from a substantially rectangular metal plate.

With regard to the air compression device 1 shown in FIG. 6, one of thepanels 12 b is removed from one of the two individual cases 12.Therefore, FIG. 6 shows an internal structure of the air compressiondevice 1.

FIGS. 3 to 6 show a coordinate system indicating directions. Each of thearrows A, B in the coordinate system shows the same directions as thearrows A, B shown in FIG. 2. Each of the two individual cases 12includes side surfaces 12 e, 12 g. The side surfaces 12 e, 12 g (c.f.FIGS. 3 and 4) are aligned with each other in the direction of the arrowA. A substantially rectangular intake port 12 c (c.f. FIG. 3) is formedin the side surface 12 e. A substantially rectangular exhaust port 12 dis formed in the side surface 12 g, The side surface 12 e extends alongthe side surface 100 b of the vehicle 100 described with reference toFIG. 2. In the present embodiment, the housing side surface isexemplified by the side surface 12 e.

Each of the two air compressor units 2 includes a first louver 21 (c.f.FIG. 3), a filter 22 (c.f. FIGS. 5 and 6) and a second louver 23 (c.f.FIG. 4). The first louver 21 and the filter 22 are attached to theintake port 12 c. The second louver 23 is attached to the exhaust port12 d. The first and second louvers 21, 23 are removed from the aircompression device 1 shown in FIG. 5. Therefore, FIG. 5 clearly showsthe filter 22.

As described above, each of the two individual cases 12 holds each ofthe two air compressor units 2. The two individual cases 12 are alignedin series in the running direction of the vehicle 100 (the direction ofthe arrow B). The aligned two individual cases 12 are integrally fixedto the vehicle 100. The two air compressor units 2, each of which isheld in the two individual cases 12, are also aligned in series in therunning direction. of the vehicle 100 (the direction of the arrow B).The case unit 11 appropriately holds the two air compressor units 2,which are aligned in the running direction of the vehicle 100.

[Overall Configuration of Air Compressor Unit]

FIG. 8 is a schematic perspective view of one of the two air compressorunits 2 shown in FIG. 6. FIG. 9 is another schematic perspective view ofthe air compressor unit 2 shown in FIG. 8. FIG. 9 is different from FIG.8 in the viewing angle. FIG. 8 shows one individual case 12 surroundingan air compressor unit 2 whereas FIG. 9 does not show an individualcase. FIG. 10 is a schematic perspective view showing an internalstructure of the air compressor unit 2 depicted in FIG. 9. FIG. 10 isdifferent from FIG. 9 in the viewing angle.

Each of the two air compressor units 2 includes an air compressor 13(c.f. FIG. 8), an electric motor 14 (c.f. FIG. 8), cooling fans 15 (c.f.FIG. 8), a base 16 (c.f. FIG. 8), an after-cooler 17 (c.f. FIG. 8), acooling fan 18 (c.f. FIG. 9), a dehumidifier 19 (c.f. FIG. 10), atransmitter 20 (c.f. FIG. 10), the first louver 21 (c.f. FIG. 3), thefilter 22 (c.f. FIG. 3), the second louver 23 (c.f. FIG. 5) and acontroller 24 (c.f. FIG. 8). The cooling fans 15 are used for coolingthe air compressor 13 (c.f. FIG. 9). The cooling fan 18 is used forcooling the after-cooler 17. The two air compressor units 2 may bestructurally identical to each other. Therefore, the followingdescription is applied to each of the two air compressor units 2.

[Air Compressor]

As shown in FIG. 8, the air compressor 13 is stored in the individualcase 12. The air compressor 13 may be a general scroll compressor. Thescroll compressor uses a swing scroll and a fixed scroll to compresssucked air and generate compressed air. The air compressor 13 maygenerate the compressed air without mixing oil into air (i.e. the aircompressor may be an oil-free air compressor).

As shown in FIG. 9, the air compressor unit includes a suction pipe 26and an air suction portion 25. A negative pressure atmosphere isgenerated in the air suction portion 25 and the suction pipe 26 underoperation of the air compressor 13. Consequently, the air outside theindividual case 12 is sucked through the air suction portion 25. Thesuction pipe 26 is connected to the air suction portion 25 and a suctionport (not shown) of the air compressor 13. The air flowing into the airsuction portion 25 flows into the air compressor 13 through the suctionpipe 26.

The air compressor unit 2 further includes a paper filter 25 b. Thepaper filter 25 b is situated in the air suction portion 25. The paperfilter 25 b traps dust (e.g. sand dust) in the air flowing into the airsuction portion 25. The air suction portion 25 designed so that anoperator takes out the paper filter 25 b. Therefore, the operator mayexchange the paper filter 25 b with a new paper filter 25 b.

The electric motor 14 drives the air compressor 13. When the aircompressor 13 is driven, oscillatory rotation happens to the swingscroll with respect to the fixed scroll in the air compressor 13. Theair flowing into the air compressor 13 through the air suction. portion25 and the suction pipe 26 is compressed between the swing scroll andthe fixed scroll, and becomes compressed air during the oscillatoryrotation.

The air compressor unit 2 further includes a discharge pipe 27. Thedischarge pipe 27 is connected to a discharge port (not shown) of theair compressor 13 and the after-cooler 17. The compressed air generatedin the air compressor 13 flows into the discharge pipe 27 through thedischarge port. The compressed air then flows into the after-cooler 17through the discharge pipe 27. The discharge pipe 27 may be made of anappropriate elastic material (e.g. polytetrafluoroethylene (PTFE)).Alternatively, the discharge pipe 27 may be a copper pipe or a steelpipe. Further alternatively, the discharge pipe 27 may be a combinationof pipe members made of an elastic material and a metal material. Theprinciple of the present embodiment is not limited to a specificstructure of the discharge pipe 27.

In the present embodiment, a scroll compressor is used as the aircompressor 13. Alternatively, a screw air compressor may be incorporatedin an air compressor unit. Further alternatively, a reciprocating aircompressor may be incorporated in an air compressor unit. In this case,a rotational drive force generated by the electric motor for driving theair compressor is changed into a reciprocation drive force by acrankshaft. The air compressor uses the reciprocation drive force tocompress the supplied air.

In the present embodiment, the air compressor 13 compresses the airwithout mixing oil into supplied air. Alternatively, the air compressorunit may include an air compressor configured to mix oil into suppliedair. The air compressor may mix the oil into the supplied air, and thencompress the air containing the oil.

[First Louver]

As shown in FIGS. 3 and 5, the first louver 21 is placed over the filter22 in the width direction of the vehicle 100 (the direction of the arrowA). The air outside the individual case 12 passes through the firstlouver 21 and the filter 22 sequentially, and flows into the individualcase 12.

FIG. 11 is a schematic enlarged front view of the filter 22. As shown inFIG. 11, the filter 22 includes main plate portions 46 which areoverlapped with each other. The coordinate system shown in FIG. 5includes the direction of the arrow F coincident with the direction ofthe arrow A. The direction of the arrow F shows the overlappingdirection of the main plate portions 46.

The first louver 21 is aligned in the overlapping direction (thedirection of the arrow F) of the main plate portions 46. The firstlouver 21 appears on the outer surface of the individual case 12.

As shown in FIGS. 3 and 5, the individual case 12 includes asubstantially rectangular attachment frame 41. The filter 22 and thefirst louver 21 are attached to the attachment frame 41. An operator maydetach the first louver 21 from the attachment frame 41. The firstlouver 21 prevents adhesion of water (e.g. rainwater) and large foreignmatters (e.g. a part of newspaper) to the filter 22.

As shown in FIG. 3, the first louver 21 includes a rectangular frame 21a and louver pieces 21 b. The frame 21 a is placed over and fixed to theattachment frame 41. Both ends of each of the louver pieces 21 b arefixed to the frame 21 a. Each of the louver pieces 21 b is a plate-likemember extending in the running direction of the vehicle 100 (thedirection of the arrow B).

The direction of the arrow C of the coordinate system in FIG. 3 showsthe vertical direction. The louver pieces 21 b are aligned in thevertical direction (the direction of the arrow C) at regular intervals.Each of the louver pieces 21 b is inclined so that the lower edge ofeach of the louver pieces 21 b is more distant from the filter 22 thanthe upper edge of each of the louver pieces 21 b is. A tip end of eachof the louver pieces 21 b (an end of each of the louver pieces 21 b inthe running direction of the vehicle 100 (the direction of the arrow B))is substantially rectangular.

[Schematic Configuration of Filter]

As shown in FIG. 9, the air passing through the filter 22 is sucked bythe air suction portion 25 or the cooling fans 15. When the air outsidethe individual case 12 passes through the filter 22, the filter 22removes foreign matters. As described above, the filter 22 is attachedto the individual case 12. In the present embodiment, one filter 22 isattached for one air compression device 1.

[Electric Motor and Controller]

As shown in FIGS. 7 to 10, the electric motor 14 is used as a drivingsource for driving the air compressor 13. The electric motor 14generates a driving force. The driving force is transmitted from theelectric motor 14 to the air compressor 13 by the transmitter 20.

Oscillatory rotation happens to the swing scroll of the air compressor13 under the transmission of the driving force to the air compressor 13.

The controller 24 (c.f. FIGS. 8 to 10) is used as a control device forsupplying an electric current from a power source (not shown) to theelectric motor 14, and controlling to drive the electric motor 14. Thecontroller 24 controls the electric current to be supplied to theelectric motor 14, and the number of rotations of the electric motor 14(the rotating speed of the electric motor 14).

[Cooling Fan for Cooling Air Compressor]

As shown in FIG. 9, the cooling fans 15 are adjacent to the aircompressor 13 in the vehicle width direction (the direction of the arrowA). The cooling fans 15 generate cooling air for cooling the aircompressor 13. The air compressor 13 is situated at the downstream ofthe cooling fans 15 in the flow direction of the cooling air. Therefore,the air compressor 13 is appropriately cooled.

Two cooling fans 15 are used for cooling one air compressor 13. The. twocooling fans 15 may be axial fans, each of which has a propeller. Thetwo cooling fans 15 are driven by an electric motor, which is providedindependently of the electric motor 14. The two cooling fans 15 arealigned in series to coaxially rotate.

A cover surrounding the propellers of the cooling fans 15 is joined to acover surrounding the air compressor 13. Therefore, the cooling airgenerated by the cooling fans 15 is efficiently fed to the aircompressor 13. Consequently, the air compressor 13 is efficientlycooled. The broken-line arrows in FIG. 7 conceptually show a flowdirection of the cooling air for cooling the air compressor 13 and aflow direction of the cooling air generated by the cooling fan 18 forcooling the after-cooler 17.

[Base]

FIGS. 8 to 10 show the base 16 made of steel. Various devices such asthe air compressor 13 and the electric motor 14 are attached to the base16. In the present embodiment, the base 16 has a flat plate shape.

The base 16 includes a first surface 16 a, which is oriented upward, anda second surface 16 b, which is oriented downward. The first surface 16a is substantially parallel to the second surface 16 b.

The air compressor 13 includes a casing, which is fixed to the firstsurface 16 a of the base 16. The electric motor 14 includes a casing 14a, which is fixed to the second surface 16 b. As shown in FIG. 9, theair compressor 13 and the electric motor 14 are aligned in the verticaldirection (the direction of the arrow C) when the air compressor unit 2is attached to the vehicle 100. The base 16 is situated between the aircompressor 13 and the electric motor 14.

The air compressor 13 is distant upward from the electric motor 14 by athickness of the base 16. The cooling fans 15 are situated above thefirst surface 16 a, to which the air compressor 13 is attached.Therefore, the cooling fans 15 are also distant upward from the electricmotor 14 by the thickness of the base 16. Therefore, the air compressor13 and the cooling fans 15 are thermally isolated from the electricmotor 14 by the base 16. In short, heat generated in the electric motorbecomes less influential to cooling of the air compressor 13 by thecooling fans 15. Accordingly, the cooling fans 15 may efficiently coolthe air compressor 13.

The controller 24 is adjacent to the electric motor 14. The controller24 is closer to the second surface 16 b, to which the electric motor 14is attached, than the first surface 16 a, to which the air compressor 13is attached. The controller 24 may or may not be fixed to the secondsurface 16 b.

In the present embodiment, the air compressor 13 and the cooling fans 15are situated on the base 16 whereas the electric motor 14 and thecontroller 24 are situated beneath the base 16 when the air compressorunit 2 is attached to the vehicle 100. Alternatively, the air compressor13 and the cooling fans 15 may be situated beneath the base 16 whereasthe electric motor 14 and the controller 24 may be situated on the base16 when the air compressor unit 2 is attached to the vehicle 100.

[Cooling Fan for Cooling After-Cooler]

As shown in FIGS. 7, 9 and 10, the cooling fan 18 is driven by a drivingforce of the electric motor 14 to feed the cooling air to theafter-cooler 17. When the cooling air is fed to the after-cooler 17, theafter-cooler 17 is cooled from the outside. The cooling fan 18 may be acentrifugal fan (e.g. a sirocco fan). As described above, the brokenline arrows in FIG. 7 show a flow direction of the cooling air towardthe after-cooler 17.

As shown in FIG. 7, a rotary shaft 18 a of the cooling fan 18 is coaxialwith a rotary shaft 13 a of the air compressor 13. The rotary shafts 18a, 13 a are linearly aligned and integrally rotated. An air suction portof the cooling fan 18 is situated near the rotary shaft 13 a of the aircompressor 13.

The cooling fan 18 is rotated by the driving force which is generated bythe electric motor 14. When the cooling fan 18 is rotated, a negativepressure atmosphere is generated near the rotary shaft 13 a of the aircompressor 13. Therefore, the air near the rotary shaft 13 a of the aircompressor 13 is sucked through the air suction port at the center ofthe cooling fan 18. The air sucked by the rotating cooling fan 18 flowsradially from the cooling fan 18. Consequently, the air flows out fromthe circumferential surface of the cooling fan 18 as cooling air.

The air compressor unit 2 includes a duct 28. The cooling air, which isgenerated by the cooling fan 18, is guided by the duct 28 toward theafter-cooler 17. The cooling air guided by the duct 28 blows onto theafter-cooler 17. Accordingly, the after-cooler 17 is cooled.

The duct 28 and a cover for the cooling fan 18 are removed from the aircompressor unit 2 shown in FIG. 10.

[Transmitter]

As shown in FIGS. 7 and 10, the transmitter 20 transmits a driving forcefrom the electric motor 14 to the cooling fan 18 and the air compressor13. The transmitter 20 includes a drive pulley 29, an idler pulley 30and a drive belt 31.

As shown in FIG. 10, the drive pulley 29 is rotated together with arotary shaft 14 b of the electric motor 14. The idler pulley 30 isrotated together with the rotary shaft 18 a of the cooling fan 18 andthe rotary shaft 13 a of the air compressor 13. The drive belt 31 is anendless belt, which is wound around the drive pulley 29 and the idlerpulley 30.

When the rotary shaft 14 b of the electric motor 14 is rotated, thedrive pulley 29 is rotated together with the rotary shaft 14 b. As aresult of circulation of the drive belt 31 with a rotation of the drivepulley, the idler pulley 30 is also rotated. When the rotary shaft 18 aof the cooling fan 18 is rotated together with the idler pulley 30, thecooling fan 18 is operated. As described above, the cooling shaft 18 aof the cooling fan 18 is coaxially and integrally rotatable with therotary shaft 13 a of the air compressor 13. Therefore, the rotary shaft13 a of the air compressor 13 is rotated together with the rotary shaft18 a of the cooling fan 18.

[After-Cooler]

The after-cooler 17 shown in FIGS. 7 to 10 cools the compressed airgenerated in the air compressor 13. As described above, the after-cooler17 is connected to the air compressor 13 via the discharge pipe 27. Theafter-cooler 17 cools the compressed air flowing through the dischargepipe 27. As shown in FIGS. 8 to 10, the after-cooler 17 is fixed to thefirst surface 16 a of the base 16.

As shown in FIG. 9, the after-cooler 17 includes a first cooler 33 and asecond cooler 34.

The first cooler 33 includes a first flow channel 35. The compressedair, which is generated in the air compressor 13, flows along the firstflow channel 35. The first flow channel 35 is cooled by the cooling air,which is generated by the cooling fans 15. As described above, thecooling fans 15 generate cooling air which flows toward the aircompressor 13. The first cooler 33 is situated at the downstream of theair compressor 13 in the flow direction of the cooling air.

As described above, the cooling air generated by the cooling fans 15cools the air compressor 13 from the outside. The cooling air then coolsthe first flow channel 35 of the first cooler 33 from the outside. Thecompressed air, which is cooled by the cooling air and flows inside thefirst flow channel 35, is cooled while the compressed air flows throughthe first flow channel 35.

The first flow channel 35 zigzags in the running direction of thevehicle 100 (the direction of the arrow B), and extends in the verticaldirection (the direction of the arrow C). The after-cooler 17 includesplate-like cooling fins 35 a. The cooling fins 35 a are attached to theouter surface of the first flow channel 35. Each of the cooling fins 35a extends in parallel to the flow direction of the cooling air from thecooling fans 15 and in the vertical direction (the direction of thearrow C).

As shown in FIG. 7, the air compressor unit 2 includes a duct 37. Theduct 37 is situated at the downstream of the air compressor 13 in theflow direction of the cooling air, which is generated by the coolingfans 15. The cooling air after the heat removal from the air compressor13 is guided to the first cooler 33 through the duct 37.

As shown in FIG. 9, the second cooler 34 is connected to the firstcooler 33. The second cooler 34 includes a second flow channel 36. Thesecond flow channel 36 is connected to a downstream end of the firstflow channel 35. The compressed air, which is cooled in the first cooler33, flows into the second flow channel 36.

The second cooler 34 is cooled by the cooling air, which is generated bythe cooling fan 18. The cooling air generated by the cooling fan 18cools the second flow channel 36 of the second cooler 34 from theoutside.

The second flow channel 36 zigzags in the running direction of thevehicle 100 (the direction of the arrow B), and extends in the verticaldirection (the direction of the arrow C). The after-cooler 17 includesplate-like cooling fins 36 a. The cooling fins 36 a are fixed to theouter surface of the second flow channel 36. The cooling fins 36 aextend in parallel to the flow direction of the cooling air from thecooling fan 18 and in the vertical direction (the direction of the arrowC). The compressed air flowing inside the second flow channel 36 iscooled by the cooling fan 18. Therefore, the compressed air, which isgenerated in the air compressor 13, is cooled in the first cooler 33,and then cooled in the second cooler 34.

The first cooler 33 is adjacent to the air compressor 13 in thedirection designated by the arrow A. The second cooler 34 is adjacent tothe cooling fan 18 in the direction designated by the arrow A. When theair compressor unit 2 is attached to the vehicle 100, the first andsecond coolers 33, 34 are aligned substantially horizontally in thedirection designated by the arrow B.

The direction of the arrow D shown in FIGS. 9 and 10 schematically showsairflow in the individual case 12. The air flows from the first louver21 to the second louver 23.

[Dehumidifier]

The dehumidifier 19 shown in FIG. 10 dehumidifies the compressed air,which is cooled in the after-cooler 17. The dehumidifier 19 is connectedto the downstream end of the second cooler 34. The compressed air cooledin the second cooler 34 flows into the dehumidifier 19.

As shown in FIG. 7, the air compression device 1 includes exit portions40. The compressed air generated in the air compressor units 2 is fedfrom the exit portions 40 to the outside of the air compression device1. Each of the dehumidifiers 19 is connected to each of the exitportions 40. The compressed air is supplied through the exit portions 40to an accumulator tank (not shown) placed in the outside of the caseunit 11. The accumulator tank stores the compressed air.

The compressed air, which is cooled in the second cooler 34, flows intothe dehumidifier 19. The compressed air is then dehumidified by thedehumidifier 19. The compressed air, which is dehumidified by thedehumidifier 19, is fed to the accumulator tank through the exit portion40.

[Structure of Filter]

The structure of the filter 22 is described below. FIG. 11 is aschematic enlarged front view of the filter (from the width direction ofthe vehicle 100 (the direction of the arrow A)). FIG. 12 is a schematicsectional view taken along the line XII-XII shown in FIG. 11. FIG. 13 isa schematic sectional view taken along the line XIII-XIII shown in FIG.11.

As shown in FIG. 5, the filter 22 is attached to the rectangularattachment frame 41 formed on the panel 12 b which forms the sidesurface 12 e of the individual case 12. An operator may detach thefilter 22 from the attachment frame 41.

The attachment frame 41 defines an opening area on the side surface 12 eof the individual case 12. The attachment frame 41 protrudes from theside surface 12 e of the individual case 12 outwardly (in the widthdirection of the vehicle 100 (the direction of the arrow A)). Theattachment frame 41 is formed along the outer edge 12 f of the sidesurface 12 e of the panel 12 b. The filter 22 is attached to the innerperipheral surface of the attachment frame 41.

The filter 22 as a whole is a rectangular member having a predeterminedthickness. The filter 22 is oriented to the outside of the vehicle 100in the width direction of the vehicle 100 (the direction of the arrowA).

As shown in FIG. 11, the filter 22 includes plate members 45. The platemembers 45 are overlapped with each other to form the filter 22. Theoverlapping direction (the direction of the arrow F) in which the platemembers 45 are overlapped with each other is substantially parallel tothe width direction of the vehicle 100 (the direction of the arrow A).The filter 22 occupies a large part (at least a half or more) of theside surface 12 e.

The air passing through the first louver 21 flows through the filter 22.The filter 22 removes foreign matters (e.g. dust) from the air. Thecleaned air flows into the individual case 12. The air passing throughthe filter 22 is sucked into the air compressor 13 and the cooling fans15 in the individual case 12. The filter 22 causes turbulence of the airpassing through the filter 22. As a result of the turbulence, theforeign matters are separated from the airflow.

As described above, the filter 22 includes the plate members 45. Amanufacturer manufacturing the air compression device 1 may perform acutting process and a bending process for a metal plate (an aluminumplate member) having a thickness in the range from about 0.1 mm to 0.2mm to manufacture a plate member 45. The filter 22 may include about tenplate members 45. FIG. 11 shows two plate members 45. The plate members45 are overlapped in the direction of the arrow F at a predeterminedinterval. The attachment frame 41 supports each of the plate members 45.

The plate members 45 are arranged away from each other in the directionof the arrow F at an interval of about 1 mm. A gap is formed between theadjacent plate members 45. Therefore, there is a decrease in pressureloss of air passing through the filter 22. In addition, the gap betweenthe adjacent plate members 45 makes it easy to wash the filter 22.Alternatively, the plate members 45 may be brought into close contactwith each other. The principle of the present embodiment is not limitedby the presence or absence of a gap between the plate members 45. In thepresent embodiment, the third direction is exemplified by the directiondesignated by the arrow F.

Each of the plate members 45 includes a main plate portion 46. Air holes47 for passing the air are formed in the main plate portion 46. The mainplate portion 46 includes convex surfaces 48 formed into a convex shape,and concave surfaces 49 formed into a concave shape. The convex surfaces48 and the concave surfaces 49 are alternately and continuously formed.Therefore, the main plate portion 46 as a whole has a wavy surfaceconfiguration. The air holes 47 are formed by the convex surfaces 48 andthe concave surface 49. In the present embodiment, the first main plateportion is exemplified by the main plate portion 46 of one of the twoplate members 45 shown in FIG. 11. The second main plate portion isexemplified by the main plate portion 46 of the other of the two platemembers 45 shown in FIG. 11.

As shown in FIG. 13, an air hole 47 extends through a plate member 45along a direction (the direction of the arrow J2) intersecting with thedirection, in which a surface 46 a of the main plate portion 46 isoriented (the direction of the arrow J1, i.e. in a direction normal tothe surface 46 a). The directions designated by the arrows J1, J2 aredifferent from the direction designated by the arrows A, F. The airflows in the direction of the arrows A, F shown in FIG. 13 before theair reaches the filter 22. The air hole 47 changes the air flowdirection from the direction designated by the arrows A, F to thedirection designated by the arrow J2. The air passes through the airholes 47, and flows into the individual case 12. In the presentembodiment, the first direction is exemplified by the directiondesignated by the arrow J1 whereas the second direction is exemplifiedby the direction designated by the arrow J2.

FIG. 13 conceptually shows an imaginary plane Q perpendicularlyintersecting with the direction of the arrows A, F. The air hole 47extends in a direction at a first intersection angle θ1 (90°>θ1>0°) withrespect to the imaginary plane Q. Preferably, the first intersectionangle θ1 may be in the range of not smaller than 30° but not larger than60°. More preferably, the first intersection angle θ1 may be about 45°.

An increase in the first intersection angle θ1 results in a decrease inpressure loss when the air passes through the air hole 47. If the firstintersection angle θ1 is excessively large, the airflow is less likelyto hit the main plate portion 46. Therefore, foreign matters are lesslikely to be separated from the airflow. This means degradation of thedust collecting effect.

If the first intersection angle θ1 is excessively small, there is highpressure loss when the airflow passes through the air hole 47.Accordingly, the air hole 47 is likely to clog. This means degradationof the dust collecting effect.

When the first intersection angle θ1 is in the range of not smaller than30° but not larger than 60°, the dust collecting effect is maintained ata high level. When the air passes through the air hole 47, the air flowdirection is changed so as to cause turbulence.

As shown in FIG. 11, the plate members 45 include plate members 451,452. The air holes 47 are formed in each of the plate members 451, 452.The air holes 47 formed in the plate member 451 are alignedsubstantially at regular intervals (e.g. at an interval P1=about 10 mm)along the direction coincident with a bending line defined by a convexsurface 48 or a concave surface 49 of the plate member 451 (thedirection of the arrow G1). In the present embodiment, the surface ofthe plate member is exemplified by the imaginary plane including thebending lines.

The air holes 47 formed in the plate member 451 are oblong holesextending along the direction of the arrow Gl. The air holes 47 formedin the plate member 452 are aligned substantially at regular intervals(e.g. at intervals of about 10 mm) in a direction along the surface 46 aof the main plate portion 46 (the direction of the arrow G2). The airholes 47 formed in the plate member 452 are oblong holes extending alongthe direction of the arrow G2. In the present embodiment, the first mainplate portion is exemplified by the main plate portion 46 of the platemember 451. The first through hole is exemplified by one of the airholes 47 which is formed in the plate member 451. The second air hole isexemplified by another of the air holes 47 which is formed in the platemember 451. The fourth direction is exemplified by the direction whichis designated by the arrow G1. The second main plate portion isexemplified by the main plate portion 46 of the plate member 452. Thethird air hole is exemplified by one of the air holes 47 which areformed in the plate member 452. The fourth air hole is exemplified byanother of the air holes 47 which are formed in the plate member 452.The fifth direction is exemplified by the direction which is designatedby the arrow G2.

The direction designated by the arrow G1 has a right angle with respectto the direction designated by the arrow G2. The air holes 47 formed inthe plate member 451 are also aligned substantially at regular intervals(e.g. at an interval P2=about 5 mm) in the direction designated by thearrow G2. The air holes 47 formed in the plate member 452 are alsoaligned substantially at regular intervals (e.g. at intervals of about 5mm) in the direction designated by the arrow G1. In the presentembodiment, the second intersection angle is exemplified by theintersection angle at which the direction designated by the arrow G1intersects with the direction designated by the arrow G2.

As described above, each of the air holes 47 is formed by combination ofa convex surface 48 and a concave surface 49. The height P3 of the airhole 47 to be defined in a direction connecting the apex of the convexsurface 48 with the bottom of the concave surface 49 is set to be about2 mm. The opening angle θ3 of the air hole 47 as viewed in theoverlapping direction (the direction of the arrow F) is set to be about110°.

The direction designated by the arrow G1 may be substantially parallelto the running direction of the vehicle 100 (the direction of the arrowB). In this case, the direction designated by the arrow G2 issubstantially parallel to the vertical direction of the vehicle 100 (thedirection of the arrow C).

The filter 22 may be vibrated by a vibrator (not shown). Alternatively,the filter 22 may be washed by an operator. Therefore, the filter 22 isappropriately cleaned. This makes it possible to reuse the filter 22.

As shown in FIG. 9, the filter 22 is adjacent to the air suction portion25. The filter 22 is aligned with the air suction portion 25 in thewidth direction of the vehicle 100 (the direction of the arrow A). Thefilter 22 is adjacent to the cooling fans 15. The filter is aligned withthe cooling fans 15 in the width direction of the vehicle 100 (thedirection of the arrow A). As described above, the arrow D in FIG. 9shows airflow in the individual case 12. The air compressor 13 and thecooling fans 15, 18 are situated at the downstream of the filter 22 inthe air flow direction in the individual case 12. As shown in FIG. 4,the exhaust port 12 d is situated at the downstream of the aircompressor 13 and the cooling fans 15, 18 in the air flow direction inthe individual case 12.

As shown in FIGS. 3 and 4, the first louver 21, the filter 22 and thecooling fans. 15 are arranged sequentially along the air flow direction(the direction of the arrow D) in the individual case 12. The aircompressor 13 and the cooling fan 18 are situated at the downstream ofthe cooling fans 15 in the air flow direction (the direction of thearrow D) in the individual case 12. The after-cooler 17 is situated atthe downstream of the air compressor 13 and the cooling fan 18 in theair flow direction (the direction of the arrow D) in the individual case12. The exhaust port 12 d and the second louver 23 are situated at thedownstream of the after-cooler 17 in the air flow direction (thedirection of the arrow D) in the individual case 12.

[Second Louver]

The second louver 23 shown in FIG. 4 is adjacent to the after-cooler 17.The air is discharged from the individual case 12 through the secondlouver 23. The second louver 23 is attached to the side surface 12 gopposite to the side surface 12 e of the individual case 12. The secondlouver 23 prevents adhesion of water (e.g. rainwater) and large foreignmatters (e.g. a part of newspaper) to the filter 22. The second louver23 is formed in a substantially upper half area of the side surface 12g. The second louver 23 covers the exhaust port 12 d formed in the sidesurface 12 g.

The second louver 23 includes a frame 23 a and louver pieces 23 b.

The frame 23 a is rectangular. The frame 23 a is attached to the panel12 b which forms the side surface 12 g. The louver pieces 23 b are fixedto the frame 23 a. Each of the louver pieces 23 b is a plate-like memberextending in the running direction of the vehicle 100 (the direction ofthe arrow B). Both ends of each Of the louver pieces 23 b are fixed tothe frame 23 a. The louver pieces 23 b are arranged in the verticaldirection (the direction of the arrow C) substantially at regularintervals. Each of the louver pieces 23 b includes an upper edge, and alower edge more distant from the after-cooler 17 than the upper edge is.Therefore, each of the louver pieces 23 b is inclined. Each of thelouver pieces 23 b has a substantially rectangular tip end in the widthdirection of the vehicle 100 (the direction of the arrow B).

[Operation of Air Compression Device]

An operation of the air compression device 1 is described. The solidlines in FIG. 7 conceptually show airflow under the operation of the aircompression device 1.

A negative pressure atmosphere is generated under operation of the aircompression device 1. The external air is sucked into the first louver21 under the generated negative pressure atmosphere, and then reachesthe filter 22. When the air reaches the filter 22, the air passesthrough each of the air holes 47 formed in the plate member 45 which isarranged on the surface of the filter 22 (c.f. FIG. 11). When the airpasses through the air holes 47 of the succeeding plate member 45, theflow direction of air is changed by the right angle. The air then flowsalong the extending direction of the air holes 47.

The air passing through the air holes 47 of one of the plate members 45is changed in flow direction by the right angle while the air passesthrough the air holes 47 of the succeeding plate member 45, and thenflows along the extending direction of the air holes 47. Whenever theair passes through one of the plate members 45, the air flow directionis sharply changed while the air passes in the filter 22. Therefore,spiral airflow is generated in the filter 22. A part of the dust in theair passing in the filter 22 is separated from the airflow by inertia.Another part of the dust hits on the plate members 45 to be separatedfrom the airflow. The dust then falls onto a lower portion of the filter22. The air after the dust removal passes through the filter 22, andthen flows into the individual case 12.

As shown in FIG. 9, the air flowing into the individual case 12 issucked into the air suction portion 25, and then flows into the aircompressor 13. The air compressor 13 is driven by the electric motor 14which is operated under control of the controller 24. The air compressor13 is cooled by the cooling air which is generated by the cooling fans15.

The air sucked through the air suction portion 25 flows into the aircompressor 13. The air compressor 13 compresses the air to generatecompressed air. The compressed air, which is generated by the aircompressor 13, flows into the after-cooler 17. The after-cooler 17 coolsthe compressed air. The compressed air passes through the first flowchannel 35 of the first cooler 33.

The cooling air generated by the cooling fans 15 cools the aircompressor 13. The cooling air then cools the first flow channel 35 fromthe outside. Accordingly, the compressed air is cooled inside the firstflow channel 35. The compressed air, which is cooled inside the firstcooler 35, passes through the second flow channel 36 of the secondcooler 34. The second flow channel 36 is cooled from the outside by thecooling air which is generated by the cooling fan 18. Therefore, thecompressed air is cooled inside the second flow channel 36.

The compressed air which is cooled by the after-cooler 17 flows into thedehumidifier 19. The dehumidifier 19 dehumidifies the compressed air.The compressed air, which is dehumidified by the dehumidifier 19, is fedthrough the exit portion 40. The compressed air is then supplied to theaccumulator tank.

The air passing through the cooling fins 35 a, 36 a of the after-cooler17 is discharged to the outside of the individual case 12 through theexhaust port 12 d and the second louver 23 (c.f. FIG. 4)

[Advantageous Effects of Air Compression Device]

According to the present embodiment, it is possible to repeatedly usethe filter 22 without discarding the filter 22. The filter 22 changesthe flow direction of air passing through the air holes 47. When the airflows through the filter 22, foreign matters with large inertia such asdust are separated from the airflow. Since the foreign matters fall offfrom the main plate portions 46 of the filter 22, there is littleadhesion of the foreign matters to the filter 22. The filter 22 isrepeatedly used by performing a washing process or a vibration process,unlike a filter structure configured so that foreign matters arefiltrated through a mesh of the filter. Therefore, it is not necessaryto exchange the filter 22 or it is possible to remarkably reduce afrequency of exchanging the filter 22. Foreign matters are less likelyto adhere to the main plate portions 46.

Therefore, it is possible to keep dust removal performance of the filter22 at a high level for a long period of time. Therefore, the aircompression device 1 may allow a reduction in maintenance cost for dustremoval without excessive degradation of the dust removal performance.

The plate members 45 are aligned in the direction designated by thearrow F. The air holes 47 of each of the plate members 45 extend in adirection at the first intersection angle 01 with the imaginary plane Qwhich perpendicularly intersects with the direction designated by thearrow F. Accordingly, the airflow passing through the filter 22 makesstrong turbulence. Foreign matters in the airflow are likely to hit themain plate portions 46. Therefore, a lot of the foreign matters areseparated from the airflow. Accordingly, the filter 22 may trap a largeamount of dust.

The air holes 47 formed in the plate member 451 are oblong holesextending in the direction designated by the arrow G1. The air holes 47formed in the plate member 452 adjacent to the plate member 451 areoblong holes extending in the direction designated by the arrow G2.

The direction of the arrow G1 has a second intersection angle θ2(180°>θ2>0°) with the direction of the arrow G2. Foreign matters in theairflow passing through the filter are likely to hit the main plateportions 46. Therefore, the filter 22 may trap a large amount of dust.

The second intersection angle θ2 may be set to 90°. In this case, thereis a large change in direction of the airflow passing through the filter22. Foreign matters in the airflow are likely to hit the main plateportions 46 in the filter 22. Therefore, the filter 22 may trap a largeamount of dust.

The direction designated by the arrow G1 may be substantially parallelto the running direction of the vehicle 100 (the direction of the arrowB). The direction designated by the arrow G2 may be substantiallyparallel to the vertical direction of the vehicle 100 (the direction ofthe arrow C). Accordingly, the dust collecting performance of the filter22 is less likely to depend on the running direction of the vehicle 100(the direction of the arrow B).

The filter 22 may occupy at least a half or more of the area surroundedby the outer edge 12 f of the side surface 12 e of the individual case12. This allows for the filter 22 to have a large opening area.Therefore, the cooling air for cooling the air compressor 13 is likelyto flow into the individual case 12 through the filter 22 while thevehicle 100 runs. The air compressor 13 and other portions which arerequired to be cooled are appropriately cooled. The entire surface ofthe filter 22 is less likely to be blocked even when a large foreignmatter (e.g. a part of newspaper) adheres to the surface of the filter22 while the vehicle 100 runs. This allows for the external air to flowinto the individual case 12 through the filter 22.

The attachment frame 41 is formed along the outer edge 12 f of the sidesurface 12 e of the individual case 12. This allows for a designer toset a large value for the opening area of the filter 22.

The attachment frame 41 protrudes outwardly from the side surface 12 eof the individual case 12. The filter 22 is situated in the attachmentframe 41. This allows for a designer to set a small value for a volumeof the individual case 12 and a large space for installation of thefilter 22. Since a variety of devices are situated in a space below thefloor of the vehicle 100, it is important to set a small volume for theindividual case 12.

Foreign matters (e.g. dust) are removed from the air by the filter 22.Therefore, clean air flows into the air compressor 13. This means thatthere is a decreased risk of foreign matters giving damage to a rotatingportion (e.g. a bearing) of the air compressor 13. The first louver 21receives water (e.g. rainwater). Therefore, water is less likely to flowinto the housing through the filter 22. The first louver 21 functions asa protection wall against the filter 22. This means that there is adecreased risk of stepping stones hitting the filter 22 while thevehicle 100 runs. In addition, the first louver 21 prevents adhesion oflarge dust to the filter 22. Since the filter 22 is less likely to besmeared, it is not necessary to frequently exchange the filter 22. Thismeans a reduction in maintenance cost of the air compression device 1.

The air compressor 13 and the cooling fan 18 are aligned in the widthdirection of the vehicle 100 (the direction of the arrow A) from thefilter 22. As described above, the air flowing into the individual caseis cleaned by the filter 22. Therefore, little dust reaches the aircompressor 13 and the cooling fan 18. This means a decreased risk ofdust giving damage to the air compressor 13 when the dust is adhered tothe main shaft of the air compressor 13. Since the air compressor isless likely to be damaged, it is not necessary to frequently perform amaintenance operation of the air compressor 13.

The paper filter 25 b may be used in combination with the filter 22. Asdescribed above, the filter 22 effectively removes foreign matters.Therefore, it is not necessary to frequently exchange the paper filter25 b.

As described above, the cooling fins 35 a, 36 a receive cooling air fromthe cooling fan 18. As described above, the filter 22 removes a largeamount of foreign matters. Therefore, the cooling fins 35 a, 36 a areless likely to be smeared. Accordingly, it is not necessary tofrequently wash the individual case 12.

The air compression device 1 is arranged along an imaginary extensionplane which extends downward from the side surface 101 b of the vehicle100 in the width direction of the vehicle 100 (the direction of thearrow A). The filter 22 is oriented toward the outside of the vehicle100. Therefore, the filter 22 is situated at the upstream in the flowdirection of traveling air of the vehicle 100. Since cool air flows intothe individual case 12 through the filter 22, various equipment in theindividual case 12 are effectively cooled. Since the filter 22 isarranged along the side surface of the vehicle 100, an operator mayeasily access the filter 22. Therefore, the operator may easily inspectand/or repair the filter 22. This means a reduction in maintenance costof the filter 22.

[Modifications]

A person skilled in the art may modify the present embodiment in variousways as far as the modifications are within a scope of the principle ofthe present embodiment.

(1) With regard to the aforementioned embodiment, the air compressiondevice 1 includes a scroll air compressor. Alternatively, the aircompression device may include a screw air compressor. Furtheralternatively, the air compression device may include a reciprocatingair compressor configured to change a rotational drive force from anelectric motor into a reciprocation drive force via a crankshaft. Theair compression device may include an air compressor for compressing theair containing oil.

(2) With regard to the aforementioned embodiment, the air compressor 13and the electric motor 14 are aligned in the vertical direction.Alternatively, the air compressor and the electric motor may be alignedin another direction.

(3) With regard to the aforementioned embodiment, two cooling fans arearranged in one air compressor unit. Alternatively, one cooling fan maybe arranged in one air compressor unit. Further alternatively, three ormore cooling fans may be arranged in one air compressor unit.

(4) With regard to the aforementioned embodiment, the air compressiondevice 1 is placed in a lower portion of the floor of the vehicle 100.Alternatively, the air compression device may be placed in a place otherthan the lower portion of the floor of the vehicle. For instance, theair compression device may be placed in an upper portion of the roof ofthe vehicle.

(5) With regard to the aforementioned embodiment, the air holes formedin one of the main plate portions are oblong holes extending in therunning direction of the vehicle whereas air holes formed in the otherof the main plate portions are oblong holes extending in the verticaldirection of the vehicle. Alternatively, the air holes may be oblongholes extending in anther direction. The principle of the presentembodiment is not limited to a specific extending direction of oblongholes.

(6) With regard to the aforementioned embodiment, the air compressiondevice is arranged along a side surface of a train coach. Alternatively,the air compression device may be arranged at the center in the widthdirection of the train coach.

(7) With regard to the aforementioned embodiment, the air compressiondevice is attached to a train coach. Alternatively, the air compressiondevice may be attached to another vehicle.

The air compression device described in the context of theaforementioned embodiment mainly includes the following features.

(1) An air compression device according to one aspect of theaforementioned embodiment includes a housing in which an air compressoris stored, the air compressor being configured to generate compressedair; and a filter through which air passes, the air being sucked intothe housing. The filter includes a plate member having a first mainplate portion provided with air holes through which the air passes. Asurface of the first main plate portion is oriented in a firstdirection, the air holes extending through the plate member in a seconddirection intersecting with the first direction so as to change a flowdirection of the air.

According to the aforementioned configuration, the air holes extend inthe second direction intersecting with the first direction, in which thesurface of the first main plate portion is oriented, to change a flowdirection of the air. Therefore, foreign matters with large inertia(e.g. dust) may be appropriately removed from the air passing throughthe filter. The foreign matters hitting the first main plate portionfall off from the first main plate portion. Therefore, the foreignmatters are less likely to adhere to the filter. Accordingly, the filtermay be repeatedly used without being thrown away, unlike a filter havinga mesh structure configured to remove foreign matters. As describedabove, the foreign matters fall off from the first main plate portion.Therefore, dust removal performance of the filter is kept at a highlevel. Accordingly, the air compression device may contribute to areduction in maintenance cost for dust removal without causing excessivedegradation in the dust removal performance.

(2) With regard to the aforementioned configuration, the filter mayinclude a second main plate portion aligned with the plate member in athird direction different from the first and second directions. Thesecond direction may have a first intersection angle with an imaginaryplane which perpendicularly intersects with the first direction.

According to the aforementioned configuration, the air passing throughthe filter causes strong turbulence. Therefore, foreign matters in theair hit the first and/or second main plate portions, and then areeffectively removed. Therefore, the filter may have high dust removalperformance.

(3) With regard to the aforementioned configuration, the air holes inthe first main plate portion may include a first air hole, and a secondair hole aligned with the first air hole in a fourth direction along thesurface of the plate member. The second main plate portion includes athird air hole extending in a fifth direction having a secondintersection angle with the fourth direction, and a fourth air holealigned with the third air hole in the fifth direction. Each of thefirst and second air holes may be an oblong hole extending in the fourthdirection. Each of the third and fourth air holes may be an oblong holeextending in the fifth direction.

According to the aforementioned configuration, a lot of foreign mattersin the air passing through the filter hit the first and/or second mainplate portions. Therefore, the filter may have high dust removalperformance.

(4) With regard to the aforementioned configuration, the secondintersection angle may be 90 degrees:

According to the aforementioned configuration, there is a large changein direction of airflow passing through the filter. Therefore, a lot offoreign matters in the airflow hit the first and/or second main plateportions. Accordingly, the filter may have high dust removalperformance.

(5) With regard to the aforementioned configuration, the seconddirection may be parallel to a running direction of a vehicle to whichthe air compression device is attached. The third direction may beparallel to a vertical direction of the vehicle.

According to the aforementioned configuration, dust removal performanceof the filter is less likely to depend on the running direction of thevehicle.

(6) With regard to the aforementioned configuration, the air compressiondevice may further include a louver facing the first main plate portion.The louver may appear on an outer surface of the housing and allowpassage of the air.

According to the aforementioned configuration, the louver receives water(e.g. rainwater). Therefore, the water is less likely to flow into thehousing through the filter. Since the louver functions as a protectionwall against the filter, there is a decreased risk of stepping stones,which hits the filter, and large dust adhering to the filter while thevehicle runs. Since the filter is less likely to be smeared, there areless frequent exchanges of the filter. This means that there is areduction in maintenance cost of the air compression device.

(7) With regard to the aforementioned configuration, the air compressiondevice may further include a cooling fan which cools the air compressorand the compressed air in the housing. The air compressor and thecooling fan may be aligned with the filter.

According to the aforementioned configuration, since the filter cleansthe air, dust is less likely to reach the air compressor and the coolingfan. Since the air compression device is less likely to be damaged, itis not necessary to frequently perform maintenance operations.

(8) With regard to the aforementioned configuration, the vehicle mayinclude a vehicle side surface along the running direction. The housingmay include a housing side surface along the vehicle side surface. Thefilter may be attached to the housing side surface. According to theaforementioned configuration, since cool air flows into the housingthrough the filter, the interior of the housing is effectively cooled.Since an operator may easily access the filter, the operator may easilyinspect and/or repair the filter. This means that there is a reductionin maintenance cost of the filter.

INDUSTRIAL APPLICABILITY

The invention is widely applicable to an air compression device which isattached to a vehicle.

This application is based on Japanese Patent Application No. 2014-137941filed on Jul. 3, 2014, the contents of which are hereby incorporated byreference.

Although the present invention has been fully described by way ofexample with reference to the accompanying drawings, it is to beunderstood that various changes and modifications will be apparent tothose skilled in the art. Therefore, unless otherwise such changes andmodifications depart from the scope of the present invention hereinafterdefined, they should be construed as being included therein.

What is claimed is:
 1. An air compression device, comprising: a housingin which an air compressor is stored, the air compressor beingconfigured to generate compressed air; and a filter through which airpasses, the air being sucked into the housing, wherein the filterincludes a plate member having a first main plate portion provided withair holes through which the air passes, and wherein a surface of thefirst main plate portion is oriented in a first direction, the air holesextending through the plate member in a second direction intersectingwith the first direction so as to change a flow direction of the air. 2.The air compression device according to claim 1, wherein the filterincludes a second main plate portion aligned with the plate member in athird direction different from the first and second directions, andwherein the second direction has a first intersection angle with animaginary plane which perpendicularly intersects with the firstdirection.
 3. The air compression device according to claim 2, whereinthe air holes in the first main plate portion include a first air hole,and a second air hole aligned with the first air hole in a fourthdirection along the surface of the plate member, wherein the second mainplate portion includes a third air hole extending in a fifth directionhaving a second intersection angle with the fourth direction, and afourth air hole aligned with the third air hole in the fifth direction,wherein each of the first and second air holes is an oblong holeextending in the fourth direction, and wherein each of the third andfourth air holes is an oblong hole extending in the fifth direction. 4.The air compression device according to claim 3, wherein the secondintersection angle is 90 degrees.
 5. The air compression deviceaccording to claim 4, wherein the second direction is parallel to arunning direction of a vehicle to which the air compression device isattached, and wherein the third direction is parallel to a verticaldirection of the vehicle.
 6. The air compression device according toclaim 1, further comprising: a louver facing the first main plateportion, wherein the louver appears on an outer surface of the housingand allows passage of the air.
 7. The air compression device accordingto claim 1, further comprising: a cooling fan which cools the aircompressor and the compressed air in the housing, wherein the aircompressor and the cooling fan are aligned with the filter.
 8. The aircompression device according to claim 5, wherein the vehicle includes avehicle side surface along the running direction, wherein the housingincludes a housing side surface along the vehicle side surface, andwherein the filter is attached to the housing side surface.